Talk:Functor hierarchy proposal
Um, it would be good if it was something like:
class (Idiom f) => Monad f where fmap f m = m >>= return . f -- or ap . return ? ap mf mv = mf >>= \f -> mv >>= \v -> return $ f v (>>=) :: f a -> (a -> f b) -> f b
Or am I missing the point?
Serhei 15:24, 29 January 2006 (UTC)
- You can't put defaults for one class in another. Though that could be another proposal. —Ashley Y 21:02, 29 January 2006 (UTC)
- Wasn't this part of John Meacham's class system proposal? What happend to this? -- Wolfgang Jeltsch 19:25, 2 February 2006 (UTC)
<*> should really be merged with
ap, right ?
(Btw, why such a symmetric operator symbol as
<* or some other assymetric one would be better .. even plain
`ap` is not so bad, imho.)
Also, it would be nice to change
mapM_ to only require
Applicative instead of
Monad. (Or one could merge these four into something like
Data.FunctorM.FunctorM, which should use
Applicative anyway.) -- StefanLjungstrand 10:18, 3 November 2006 (UTC)
I think it makes sense to take return out of Applicative. Either into a separate step between Functor and Applicative, or into a new class altogether:
class Boxable f where return :: a -> f a class (Functor f, Boxable f) => Applicative f where ...
But maybe this is just overengineering.
Twanvl 21:46, 15 January 2007 (UTC)